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湖南桃江稻瘟病菌遗传多样性分析及无毒基因的鉴定
Genetic Diversity Analysis and Identification of Avirulence Genes for Magnaporthe oryzae in Taojiang,Hunan
【摘要】 [目的]为明确湖南桃江地区稻瘟病菌遗传多样性和无毒基因的组成及变化趋势。[方法]利用8对SSR引物对2017年从湖南桃江病圃多个晚稻品种上分离纯化的29个稻瘟病单孢菌株进行遗传多样性分析,并利用18个已知抗瘟基因的水稻近等基因系(NILs)对其中的19个特异性稻瘟病菌株进行无毒基因鉴定。[结果]在相似系数0.70,差异系数0.30水平下,29个供试菌株可划分为7个宗谱,优势宗谱I有12个菌株,占参测菌数的41.3%,宗谱V有7个菌株,占总菌数的24.1%,其余5个宗谱分别有1~3个菌株,占总菌数的34.6%;通过无毒基因鉴定18个菌株致病频率(致病频率=感病水稻数/所有测试水稻品种数×100%)在35%~75%。强致病力菌株(致病频率≥70%)3株,占总菌数的15.7%;较强致病力菌株(70%>致病频率≥50%)7株,占总菌数36.8%;中等致病力菌株(50%>致病频率≥20%)9株,占总菌数的47.5%;供试菌株平均致病频率为49.86%。19个菌株对NILs水稻品系毒力频率(毒力频率=对测试水稻品系有毒力的菌株数/所有菌株数×100%)超过70%的抗性基因为Pi-k~s、Pi-z~t、Pi-ta,属强毒力菌株;毒力频率介于50%~70%的抗性基因为Pi-k~p、Pi-z~5、Pi-t、Pi-sh、Pi-5,属于中等毒力菌株;对其余抗性基因的毒力频率低于50%。[结论]湖南桃江稻瘟病菌群体具有丰富的遗传多样性,而且存在复杂的致病性分化;抗性基因Pi-3、Pi-i、Pi-11、Pi-19、Pi-12对桃江地区稻瘟病菌抗性优良,可在抗病育种中加以利用。
【Abstract】 [Objective]The present paper aimed to clarify the genetic diversity and composition of non-toxic genes of Magnaporthe oryzae in Taojiang.[Method]Genetic diversity of 29 M.oryzae isolated and purified from several late rice varieties in Taojiang disease nursery was analyzed by 8 pairs of SSR primers.And nontoxic gene of 19 isolates were identified through 18 near-isogeniclines(NILs)whose resistance gene to blast were known.[Result]The results indicated that under the 0.70 similarity coefficient and 0. 30 difference coefficient level,the total isolates of twenty-nine could be divided into seven genealogies.The dominant genealogy I contained 12 isolates,accounting for 41.3 % of the total isolates.The V genealogy contained 7 isolates,accounting for 24.1 % of the total isolates.The other 5 genealogies contain 1-3 isolates,accounting for 34.6% of the total number of isolates.The pathogenic frequency(pathogenic frequency = the number of susceptible rice varieties/the number of total tested rice varieties x 100 %)ranged from 35 % to 75 %,and there were 3 strong pathogenic isolates(pathogenic frequency>70 %)which accounted for 15.7 % of the total isolates;7 isolates were highly pathogenic(70%>pathogenic frequency≥50%),accounting for 36.8 %of the total isolates.Nine medium pathogenic isolates(50 %>pathogenic frequency≥20%),accounted for 47.5 % of the total isolates,and the average pathogenic frequency of the tested isolates was 49.86%.The virulence frequencies of 19 isolates to NILs(virulence frequencies = the number of isolates to be tested the virulence with NILs/the number of all isolates x 100 %)were identified by avirulence gene,it was shown that more than70% of the virulent genes what with highly virulent were Pi-k~s,Pi-z~t and Pi-ta.The resistance gene whose virulence frequency was between50 % and 70% with medium virulence werepi-k~p,pi-z~5,pi-t,pi-sh and Pi-5.The virulence frequency of the other resistance genes was less than 50%.[Conclusion]The population of Pyricularia oryzae in Taojiang,Hunan province has abundant genetic diversity and complicated pathogenicity differentiation.The resistance genes Pi-3,Pi-i,Pi-11,Pi-19 and Pi-12 have excellent resistance to M.oryzae in Taojiang area and can be used in disease resistance breeding.
【Key words】 Magnaporthe oryzae; SSR; Genetic diversity; Avirulence gene;
- 【文献出处】 西南农业学报 ,Southwest China Journal of Agricultural Sciences , 编辑部邮箱 ,2019年09期
- 【分类号】S435.111.41
- 【被引频次】3
- 【下载频次】119